Effect of the hybrid composition on the physicochemical properties and morphology of iron oxide–gold nanoparticles

Hybrid nanoparticles (HNPs) formed from iron oxide cores and gold nano-shells are becoming increasingly applicable in biomedicine. However, little investigation has been carried out on the effects of the constituent components on their physical characteristics. Here we determine the effect of polymer intermediate, gold nano-shell thickness and magnetic iron oxide core diameter on the morphological and physical properties of these nano-hybrids. Our findings suggest that the use of polymer intermediate directly impacts the morphology of the nanostructure formed. Here, we observed the formation of nanosphere and nano-star structures by varying the cationic polymer intermediate. The nano-stars formed have a larger magnetic coercivity, T2 relaxivity and exhibited a unique characteristic nano-heating pattern upon laser irradiation. Increasing the iron oxide core diameter resulted in a greater T2 relaxivity enhanced and nanoheating capabilities due to increased surface area. Increasing the gold nano-shell thickness resulted in a decreased efficiency as a nano-heater along with a decrease in T2 relaxivity. These results highlight the importance of identifying the key traits required when fabricating HNPs in order to tailor them to specific applications.